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This work analyses the chronology of fluvial terrace sequences of the two most important fluvial basins from central Spain draining to the Atlantic Ocean (Upper Tagus and Duero drainage basins). Both basins evolved under similar Mediterranean climatic conditions throughout the Pleistocene and present comparable number of fluvial terraces (16–17) after excluding the higher terrace levels of the Tagus (T1–T5) entrenched in the Rana surface. These higher “ranizo terraces” was formed in response to fan-head trenching in this high alluvial piedmont (+220 m) and therefore not properly controlled by Quaternary fluvial downcutting. The study accomplishes the implementation of multiple regression analyses for terrace height-age relationships. To transform relative terrace heights above the present river thalwegs (i.e. +100 m) in numerical ages a “height-age transference function” has been developed on the basis of preliminary statistical geochronological approaches proposed for Central Spain. The resultant height-age transference function gather 73 published geochronological data for terrace sequences, featuring a 3rd Order Polynomial Function (R2 0.90). This function describes the overall trend of valley downcutting for the last c. 2.3 Ma in Central Spain and is used to assign numerical ages to terrace levels at different relative elevation.

by Witold Zuchiewicz and Jerzy Zasadni (2012) intended for this volume YOUNG TECTONICS OF THE OUTER WESTERN CARPATHIANS IN THE LIGHT OF SOME MORPHOMETRIC INDICES In this paper, we test the applicability of some morphometric indices commonly used in tectonic-geomorphological studies to the area of the Outer Western Carpathians representing an Alpine fold-and-thrust belt. This belt was shaped largely in Miocene times and shows traces of Pliocene-Quaternary tectonic activity consisting mainly in some remnant folding and faulting. This is indicated by scarce examples of faulting within Quaternary strata, numerous cases of clast fracturing owing to palaeoearthquakes of relatively large magnitudes, as well as warping and tilting of Pleistocene and Holocene strath terraces. Analysis of selected morphometric indices (valley floor width-valley height ratio, riverbed gradients, stream length-gradient index, basin elongation ratios and others), conducted for the entire region and some chosen test areas in the westernmost part of the Outer Western AC C EP TE D M AN U SC R IP T ACCEPTED MANUSCRIPT 24 Carpathians, proved their usefulness in detecting zones showing tendencies to young surface uplift. However, in the case of the stream length-gradient index (SL, Hack’s index) a word of caution should be added, since the index is extremely sensitive to lithologic contrasts in the bedrock and its applicability to young tectonic analysis of fold-and-thrust belts appears to be strongly limited. Dr Andrzej Piotrowski, apiot@pgi.gov.pl, Szczecinie Panstwowy Instytut Geologiczny, Szczecin, Poland and Dr Klaus Reicherter, RWTH Aachen University, Germany

The Arriaga Palaeolithic sites, located within the Middle–Late Pleistocene thickened terrace (TCMZ: + 18–22 m) of the Manzanares River valley (Madrid, Central Spain), were subject to intensive archaeological and palaeontological prospecting during the 1980s. Compilation of documents from these old excavations, together with new geoarchaeological, sedimentological, pedological and geophysical data, allow us to locate the morpho-stratigraphic position of the analysed sites within the overall stratigraphy of the TCMZ. This thickened terrace comprises two main fluvial sequences (Lower and Upper) topped by a thick (2.5–5 m) alluvial–colluvial formation. The fluvial sequences are stacked in the study site located in the lowermost reach of the valley, but display complex inset relationships upstream, where they are individualized in two different terrace levels at + 18–22 and + 12–15 m. Terrace thickening was primarily controlled by synsedimentary subsidence caused by dissolution of the evaporitic substratum and locally influenced and backfed by tectonic activity. The regional analysis of the dated (TL and OSL) fluvial sequences containing Palaeolithic sites within the TCMZ, together with new TL dates provided in this study, indicate that the three sedimentary sequences in the TCMZ are time-transgressive valley-fill bodies. Terrace thickening started before the Last Interglacial Period (MIS 6 or older) and continued during whole MIS 5 (lower fluvial sequence) and MIS 4 (upper fluvial sequence) reaching the MIS 3 (top alluvial formation), the latter characterized by the accumulation of alluvial–colluvial sequences derived from the main tributaries and valley slopes. The TCMZ records the Middle–Late Pleistocene boundary, but also the transition between the Lower and Middle Palaeolithic periods during the Late MIS 5 (ca. 96 to 74 ka). The studied Arriaga sites contain evolved Lower Palaeolithic industry (evolved Acheulean techno-complexes) and warm faunal assemblages located within the Lower fluvial sequence, but apparently well constrained Middle Palaeolithic sites are placed within the Upper fluvial sequence at other upstream locations. Deposition of the thickened alluvium was mainly controlled by the upstream advance of dissolution-induced subsidence phenomena, blurring the impact of Late Pleistocene climatic cycles and producing time-transgressive longitudinal valley-fill bodies (i.e. sedimentary sequences). Late Quaternary climatic changes only seem to control the incision/aggradation cycles after the termination of the TCMZ from the Late MIS 3. Dates related to the development of younger inset terraces indicate that they are apparently linked with cold Heinrich events H4 to H1. These younger inset terraces yield cold faunal assemblages and abundant Middle Palaeolithic “Mousterian” assemblages, Departamento de Geología, Escuela Politécnica Superior de Ávila, Universidad de Salamanca, España, Departamento de Arqueología, Paleontología y Recursos Culturales, Auditores de Energía y Medio Ambiente, S.A., España, Departamento de Edafología, Universidad Politécnica de Madrid, España, Dirección General de Patrimonio Histórico, Comunidad de Madrid, España, Técnicas Geofísicas S.L., España, Departamento de Geología y Geoquímica, Universidad Autónoma de Madrid, España, Área de Investigación en Peligrosidad y Riesgos Geológicos, Instituto Geológico y Minero de España, España

The Roman archaeological site of Baelo Claudia (Cadiz, south Spain) is located within the Gibraltar Arch, a region with no significant recent or historical seismicity. However, previous studies have emphasized the occurrence of repeated strong archaeoseismic damage (intensity IX MSK) at Baelo Claudia tentatively bracketed in this study around AD 40–60 and AD 260–290. A multidisciplinary study has been carried out including the detailed mapping of surface deformation and building damage, surface geology and geomorphology, collection of structural data, and an extensive ground penetrating radar (GPR) survey. The obtained data are not conclusive when considered separately, but evident links between archaeoseismic damage, structural and GPR data indicate that the destruction of the city was linked to seismic shaking. The analysis of the pattern and orientation of deformation clearly indicates SW–NE directed compression due to ground shaking. This analysis also focuses on localized landslides and liquefaction processes, which appear to be coeval with the earthquakes, but the poor geotechnical parameters of the clayey substratum were determinant to amplify the observed level of destruction. The application of the present Spanish seismic code (NCSE-02) indicates that intensity VIII MSK (0.24–0.26 g) can be reached in this zone for 500 year return periods. Previous studies reported on the occurrence of repeated strong archaeoseismic damage (intensity IX MSK) in the ancient Roman city of Baelo Claudia (first to fourth centuries AD), located at the axial zone of the Gibraltar Strait in southern Spain (Menanteau et al. 1983; Goy et al. 1994; Silleres 1997; Silva et al. 2005, 2006). The archaeological stratigraphy of the city evidences two major episodes of abrupt city destruction tentatively bracketed during AD 40–60 and AD 350–395, separated by an intervening horizon of demolition for city rebuilding (Silleres 1997; Silva et al. 2005), elsewhere interpreted as characteristic of many earthquake-damaged archaeological sites in the Mediterranean (i.e. Stiros 1996; Marco et al. 1997; Hancock & Altunel 1997; Stiros & Papageourgiu 2001; Altunel et al. 2003). The urban geology and general geomorphological features of the study area are described in the previous works of Borja et al. (1993), AlonsoVillalobos et al. (2003) and Silva et al. (2005), evidencing that the Roman city was differentially founded on plastic clayey substratum, Late Quaternary sandy and clayey materials thickening to the coast (up to 5 m thick), and a variable amount of poorly compacted Roman artificial fillings. In addition, all these materials are characterized by poor geotechnical parameters, including high swelling rates for the underlying clayey substratum (Borja et al. 1993). In detail, Silva et al. (2005) From: REICHERTER, K., MICHETTI, A. M. & SILVA, P. G. (eds) Palaeoseismology: Historical and Prehistorical Records of Earthquake Ground Effects for Seismic Hazard Assessment. The Geological Society, London, Special Publications, 316, 93–121. DOI: 10.1144/SP316.6 0305-8719/09/$15.00 # The Geological Society of London 2009. applied the existing seismic code of Spain (NCSE-94 1997) concluding that it will be necessary to invoke site effect amplification to link the observed damage (over VIII–IX MSK) with local seismic sources. On the other hand, these authors dismiss linking the observed ground deformations with the wellknown AD 365 Crete tsunami event as earlier proposed by other authors (Menanteau et al. 1983), because no evidence of tsunami-related damage is recorded in the ruins. However, recent findings in small fluvial outlets east of Baelo Claudia indicate probable tsunami occurrences in cal. 2150–1825 BP (Alonso-Villalobos et al. 2003) and again in the fifteenth and sixteenth centuries (Becker-Heidmann et al. 2007) in Bolonia Bay. The tsunami event during Roman times is geologically well documented along the Spanish Atlantic coast of the Gibraltar Strait from the Donana marshlands to Cadiz (Lario et al. 2001; Luque et al. 2002; Ruiz et al. 2004) and might correspond with one of the three historically documented tsunamis that occurred between 219 BC and 60 BC in this zone (Campos 1991; Luque et al. 2001). Nevertheless, strong seismic events occurred during the Roman period, presumably affecting southern Spain: the AD 33, AD 346 and AD 382 earthquakes are listed in the Spanish seismic catalogues (i.e. Galbis 1932; Martinez Solares & Mezcua 2002). All these events are poorly documented and supposedly related to the far-field Cape of San Vicente seismic source, responsible for the AD 1775 Lisbon event (Campos 1991; Luque et al. 2001). Dates of some of these historic events match with the assumed ages of AD 40–60 and AD 365–395 proposed for the two events of destruction recorded at Baelo Claudia (Menanteau et al. 1983; Silva et al. 2005). However, even these relatively strong earthquakes produced only ground motions of moderate intensities in the Gibraltar Strait region between VI–VII MSK (Martinez Solares et al. 1979) and V–VI EMS (Martinez Solares 2001) as recorded during the AD 1775 Lisbon event. Ground motions leading to these intensities are insufficient to explain the extensive destruction of the city, making it necessary to consider and check the specific site effect amplification at Baelo Claudia. In any case, an important limitation of archaeoseismological data is that they generally do not allow identification of the causative seismic source (i.e. capable fault) producing the observed architectural disruptions (Hancock & Altunel 1997; Altunel et al. 2003; Similox-Tohon et al. 2006). Additionally, in the particular case of Baelo Claudia, most of the observed archaeoseismological disruptions can be classified as secondary effects of ground shaking (Silva et al. 2005), but might have also been produced by other natural hazards (landslides, ground subsidence, soil creep, etc.) under specific climate and weather conditions. Therefore, thoughtful research is necessary to identify the true nature of the observed deformations by means of analysis of their surface and subsurface records. We tend to divide the observed archaeoseismological damage into two groups: (1) release of impulse-like high energy during seismic events and rupture-like processes; and (2) low energy events, mainly due to gravitational forces, producing ‘slow’ processes, like creep and landslides. This work focused on the detailed mapping of surface deformations and architectural disruptions within the ancient urban zone of Baelo Claudia, in order to determine the extension, nature and structural pattern of the recorded deformations as earlier performed for other archaeological sites in the Mediterranean zone and central Europe (Korjenkov & Marzor 1999; Hinzen & Schutte 2003; Monaco & Tortorici 2004; Similox-Tohon et al. 2006). Measurement of structural data on fractures, cracks, shocks, and pop-up structures affecting the ancient Roman pavements and walls, directions of collapse of columns, houses and city walls, offer enough data to discuss the directivity and pattern of the ground movement triggering the observed architectural destruction. Therefore, we use these kinematic indicators preserved in the ruins in order to probe the directional nature of the deformations to separate effects caused by the eventual progressive ruin and burying of the city from those pointing to seismic shaking. Geophysical analysis of subsurface archaeological remains by means of an extensive ground penetrating radar (GPR) survey has been carried out in order to determine the depth extension of the observed surface deformations. Additionally GPR data have been probed to offer quality information about the subsurface location of probable event horizons. Geodynamic setting of the Gibraltar

Coastal response to tectonic activity and eustatic-climate interactions during the Late Pleistocene and Holocene has been analyzed along the Barbate-Trafalgar shoreline. The study area consists of an uplifted platform (La Breña, ∼ 140 m) bounded by two major NW-SE faults that have created two subsiding areas: Meca in the west and Barbate in the east. The areas of subsidence have favoured the accumulation of a thick morphosedimentary sequence consisting of (in ascending stratigraphic order) beach, alluvial, and aeolian deposits, which repeatedly underwent soil-forming processes. This study outlines the palaeogeographical evolution of the area over the last ∼ 140 ka, as deduced from geomorphological mapping associated with a range of laboratory analyses (mineralogical, geochemical, magnetic susceptibility, and soil micromorphology analyses), optically stimulated luminescence (OSL dating), and existing U-Th dating. Special attention has been paid to the alluvial unit, made up of vertically stacked sandy sheet-flood deposits with interbedded red paleosols. OSL ages suggest that sediment supply to the alluvial/coastal environments took place mainly at the end of the two most recent glacial periods (Oxygen Isotopic Stage [OIS] 6 and OIS 3/OIS 2) and during the last interglacial period (end of OIS 5). This means that although alluvial sedimentation took place at times of relatively high sea level, these were not times of highstand because very high sea levels (like the present) allow marine erosion of the distal part of the fans (fan toes), cutting cliffed coasts. The repeated occurrence of paleosols in the alluvial sequence seems to indicate a recurrence of environmental changes that modified the feedback relationships between the catchment and the coastal areas. These changes are recorded in repeated oscillations of soil parameters, and are revealed from the results of geochemical and environmental magnetism analyses. We associate repeated pedogenesis and alluvial sedimentation with the glacial/interglacial global climatic changes due to an oscillating humidity/aridity ratio rather than with cyclicity in thermal regime., This research has been funded by Projects BTE 2002-1065 and BTE 2002-1691; CGL 2005-01336/BTE and CGL 2005-04655/BTE; Consolider - Ingenio 2010 - GRACCIE. It is also a contribution to Projects INQUA “Marine and Terrestrial Processes”, IGCP 495, and UCM Workgroup 910198.

Thick laminar calcrete profiles are common on the surface of the eastern Canary Islands of Lanzarote and Fuerteventura. This paper reports the study of one profile from Lanzarote (Macher profile) and one from Fuerteventura (Tef|¨a profile). These profiles are about 2 m thick. The Macher profile is developed on basaltic host rocks and consists of two main horizons: a lower horizon in which white veins of laminated micrite penetrate cracks, and an upper laminar horizon. The Tef|¨a profile is cumulative and consists, from base to top, of massive, laminar, and massive and laminar-brecciated horizons. Highlighted in the study of these profiles are the presence of ooids, the complex structure of the laminar horizons, and the occurrence of fossil bee nests (Celliforma). Ooids consist of a nucleus of clay, micrite and etched grains coated with envelopes of micrite and clay (mainly palygorskite). Organic films favoured both the precipitation of carbonate and the adhesion of clays when the ooids formed in the soil. The laminar horizons consist of a centimetre-scale alternation of massive micrite with varied amounts of ooids and detrital grains with laminated micrite. This alternation indicates the small-scale periods of sedimentation, erosion and soil formation in the upper part of a relatively stable surface. These small-scale alternations may reflect climatic vegetation changes in which arid periods are represented by micrite with ooids, while laminated micrite reflects a better-developed vegetation of the wet periods. Celliforma occur as ovoid larval cells with more or less rounded bases and a flat top. The cells are about 3 cm long and 1.5 cm in diameter. Their wall is about 5 mm thick, and is commonly laminated. Celliforma is interpreted as fossil nests of solitary bees. Their presence in the laminar horizon is evidence for the existence of a vegetation cover containing angiosperms.

The tectonic Guadalentin Depression is an elongated Quaternary sedimentary basin generated by a system of left-lateral strike-slip faults on the eastern Betic Cordillera. The Lorca-Alhama de Murcia fault (LAF) is the most relevant structure, controlling the 100-km-long western margin of the depression with a prominent mountain front. Climatic conditions are semiarid, and sedimentation is dominated by alluvial fans. The interaction between tectonics, alluvial sedimentation, and climate results in the development of widespread tectonic landforms and alluvial fan surfaces with different degree of calcrete development. The variable morpho-sedimentary arrangements record different styles of faulting and uplift history on the range front faults. Large fans occur associated with the main gaps and step-overs between the different fault segments bounding the Quaternary basin (e.g. Lorca Fan). Telescopic fan sedimentation under limited distal aggradation eventually turned into distal trenching throughout the late Holocene. This geomorphic evolution constitutes a good example of the transformation of the ancient main fan-feeding channel into a true fluvial channel (present-day Guadalentin River) linked to a well-preserved Late Bronze geoarcheological record.

Conventionally, a fall in base level is seen as stimulating incision into the distal zones of alluvial fans. In the Cabo de Gata ranges of southeast Spain evidence exists to the contrary. Two sets of Quaternary coastal alluvial fans demonstrate the interaction between climatically-driven variations in the supply of sediment and eustatically-driven changes in base level. The fans are supplied from Miocene volcanic terrain within which no evidence can be found for major tectonic deformation during the period of fan development. The evolution of the east-coast fans has been affected by variations in sediment supply and changes in sea level. The west-coast fans were buffered from the effects of changes in sea level by coastal barriers. Three phases of past sedimentation can be identified on the fans. These can be differentiated on the basis of field observations of soil profiles (particularly colour of the B horizons and accumulation of CaCO3), and laboratory analyses of sequential iron oxide extractions and magnetic mineral properties. The two earlier (major) sedimentation phases were coincident with global glacials (>ca. 135 ka and ca.85-10 ka, based on the stratigraphy and uranium/thorium dating of the coastal sediments). High sea levels during the intervening interglacial and during the Holocene caused erosion of the distal zones of the east-coast fans which led to channel incision into the fan surfaces. On the west-coast fans no such incision occurred, simply proximal incision by small fanhead trenches. The youngest (relatively minor) phase of fan sedimentation has occurred during the Holocene. These contrasting contexts have produced differing styles of fans, with telescopic fan morphology on the east-coast and stacked morphology on the west-coast fans. The differences are reflected in the fan profiles, with steeper gradients dominating the east-coast fans, and extensive lower gradient distal surfaces on the west-coast fans. Fan morphometry, based on analysis of the residuals from drainage area to fan area and gradient regressions, also differentiates between the fan contexts. The fan building phases appear to be controlled proximally by climatically-driven pulses of sediment supplied to the fans. These occurred during global glacials coincident with low sea levels, and caused fan progradation onto the exposed foreshore. The intervening global interglacials were times of little fan sedimentation, and on the east coast, where high sea levels were able to erode the fan toes, deep through-fan dissection ensued., This research has been partially supported by the British Council/Spanish Government—Acciones Integradas Programme. Diane Spivey helped with some of the field surveying. John Dearing gave help in the interpretation of the mineral magnetic data. We also thank the staff of the Graphics section of the Department of Geography, University of Liverpool for producing most of the illustrations.

Three-dimensional patterns of soft-sediment deformation, affecting middle Pleistocene fluvial deposits in the Lower Manzanares Valley (SW Madrid City), are reported. They promote a small-scale hummocky topography, defined by different-sized domes, mud volcanoes, wavy ridges and fissures on an ancient flood plain surface. Related channel fill deposits are pervasively dewatered, indicating liquefaction. The sedimentological context reveals that the deformation of both floodplain surface and channel-fill deposits, were contemporaneous (singular deformed level) and generated at, or near, the ground surface; this rules out the possibility of sediment-loading and indicates a possible earthquake-induced origin.

This work illustrates the state of the art on archaeoseismology of the ancient Roman city of Baelo Claudia (Tarifa, Cadiz) after nearly fifteen years of research. This ancient Roman site was affected by two earthquakes in the years AD 40–60 and AD 260–290 which promoted important urban and architectural changes and eventually the destruction and further abandonment of the city in AD 365–390. Earthquake Archaeoseismological Effects (EAEs) are catalogued, described and mapped in the entire monumental sector of the city mainly witnessing the last earthquake which occurred in AD 260–290. Mapping of oriented EAEs illustrate damage distribution all over the lower sector of the city, as well as the occurrence of suspect coseismic landslide and tsunami events. The structural analysis of oriented EAEs throughout the entire mapped sector suggests that the intervening ground motion was preferentially oriented in a SW to NE direction. The geoarchaeological analysis and some relevant archaeological anomalies, strongly suggest the occurrence of coeval tsunami events during both ancient earthquakes, pointing to the occurrence of an offshore seismic source SSW of the city. Several N-S normal faults have been identified around the Bolonia Bay area and some of them continue offshore SSW of Baelo Claudia. These faults with clear Quaternary activity can be considered as the more probable seismic sources for the events affecting the ancient Roman site and they are consistent with the mapped damage orientation displayed by the structural analysis of EAEs within the old Roman city.

This study analyses coastal geomorphic responses to the various sea-level changes that occurred throughout the Quaternary period in the Mediterranean and Atlantic coasts of Spain. Particular emphasis is paid to the geomorphic and stratigraphic record of the changes in amplitude, duration and frequency associated with the major gradual climate changes observed in marine cores and ice oxygen-isotope records during the Early and Middle Pleistocene (ca. 2.6 Myr; ca. ~ 1.4–0.8 Myr; ca. ~ 0.4–0.2 Myr) and also with the rapid and abrupt Late Pleistocene and Holocene climate changes. With this aim, the best preserved and most complete sedimentary sequences known in the Spanish Mediterranean and Atlantic coasts covering diverse geodynamic and climatic contexts were selected and analyses. This study is mainly based on field investigation of geomorphic, sedimentologic and stratigraphic features of mapped morphosedimentary units, combined with reliable chronological data. The analyses include the interpretation of sedimentary environments, the 3-D reconstruction of facies and morphosedimentary unit arrangement, paying special attention to the lateral geomorphic relationships between marine and terrestrial morphosedimentary units developed during interglacials under sea-level highstand scenarios. The interglacials occurred during four key Quaternary periods might be related with major gradual changes associated with glacial climate cycles reported from marine and ice oxygen-isotope records. Almost coeval changes in geomorphological styles are reported from all studied areas, regardless of their specific geodynamic context. Results from the Mediterranean realm suggest that this area is more sensitive to climatic and sea level variability than the Spanish Atlantic coast, particularly in the case of rapid and abrupt changes.

Active tectonics within the Upper Tagus Basin is related to the lithospheric flexure affecting the Palaeozoic basement of the basin. This flexure displays NE-SW trending. Besides, this structure is in agreement with the regional active stress field defined by the maximum horizontal stress with NW-SE trending. In this tectonic framework, irregular clusters of instrumental seismicity (Mw< 5.0) fade in the zone bounded by the Tagus River and the Jarama River valleys. These clusters are related to major NW-SE trending faults of suspected strike-slip kinematics. Moreover, reverse faults with NE-SW trending are affected by the strike-slip system as well. Despite the reverse faults are in agreement with the present SHMAX orientation, though, they apparently are blocked as seismogenic sources (scarce instrumental seismicity recorded today). In addition, we have determined the regional and local stress/ strain fields and two different fracture patterns were observed. Hence, we have divided the area in two zones: (1) the lateral bands of the basin, defined by reverse faulting (NE-SW trending) and strike-slip faulting (NW-SE trending) and (2) the central zone of the basin characterized by shallow normal faulting and NE-SW trending strike-slip faults. Furthermore, surface faulting and liquefaction structures are described affecting Middle to Late Pleistocene fluvial deposits, suggesting intrabasinal palaeoseismic activity (5.5 < M < 6.5) during the Late Quaternary. The obtained structural and tectonic information has been used to classify and characterize the Upper Tagus Basin as a semi-stable intraplate seismogenic zone, featured by Pleistocene slip-rates < 0.02 mm/yr. This value is low but it affords the occurrence of Pleistocene paleoearthquakes.

Instrumental and historical seismicity in the Albacete province (External Prebetic Zone) has been scarcely recorded. However, major strike-slip faults showing NW-SE trending provide geomorphologic and paleoseismic evidence of recent tectonic activity (Late Pleistocene to Present). Moreover, these faults are consistently well oriented under the present stress tensor and therefore, they can trigger earthquakes of magnitude greater than M6, according to the lengths of surface ruptures and active segments recognized in fieldwork. Present landscape nearby the village of Hellin (SE of Albacete) is determined by the recent activity of the Pozohondo Fault (FPH), a NW-SE right-lateral fault with 90 km in length. In this study, we have calculated the Late Quaternary tectonic sliprate of the FPH from geomorphological, sedimentological, archaeoseimological, and paleoseismological approaches. All of these data suggest that the FPH runs with a minimum slip-rate of 0.1 mm/yr during the last 100 kyrs (Upper Pleistocene-Holocene). In addition, we have recognized the last two major paleoearthquakes associated to this fault. Magnitudes of these paleoearthquakes were gretarer than M6 and their recurrence intervals ranged from 6600 to 8600 yrs for the seismic cycle of FPH. The last earthquake was dated between the 1st and 6th centuries, though two earthquakes could be interpreted in this wide time interval, one at the FPH and other from a far field source. Results obtained here, suggest an increasing of the tectonic activity of the Pozohondo Fault during the last 10,000 yrs., Instituto Geológico y Minero de España, España, Universidad Michoacana de San Nicolás de Hidalgo, México, Facultad de Ciencias, Universidad Autónoma de Madrid, España, Departamento de Geología, Escuela Politécnica Superior de Ávila, Universidad de Salamanca, España, United States Geological Survey, Estados Unidos

Digital analysis of torrential gullies (‘barrancos’) deeply incised into the volcanic Island of Gran Canaria (Canary Islands) allows us to extract the longitudinal profiles and pre-incision surfaces for individual basins, from which morphometric parameters (length, elevation, area, slope) have been calculated. Other derived parameters, such as ridgeline profiles, maximum incision values, volume removed by fluvial erosion, geophysical relief and isostatic uplift, have also been computed. Based on K/Ar ages for the island, well-constrained incision-uplift rates have been calculated by means of the combination of different methodological approaches commonly used in orogens and large mountain ranges. The geomorphological and morphometric analyses reveal that the island is clearly divided into four environmental quadrants determined by the combination of a couple of key-factors: the age of the volcanic surfaces and the climatic conditions. These factors determine a young sector covered with Plio-Quaternary platform-forming lavas (finished at 1.9–1.5 Ma) evolving under contrasting wet (NE) to dry (SE) climates, and an older sector, conserving the residual surfaces of the Miocene shield building (14.5–8.7 Ma) at the ridgelines, also subjected to wet (NW) and dry (SW) climates. Incision is related to the age zonation of the island. Maximum incisions (

The Lorca alluvial fan (SE Spain) constitutes an excellent example of transition from alluvial to fluvial sedimentary environments in a semiarid region. The fan body represents a large gently-sloping alluvial fan of mainly sandy–silty composition. It is presently dissected throughout its length by the Guadalentín River, which worked as the main fan channel and still operates as a torrential rambla-type channel responsible for historic large flood events. Three different outcrops are analysed at fan-apex, mid-fan and distal-fan locations, taking also into account the different inset terrace levels developed within the main fan trench at + 8–9 m, + 5–6 m, + 3–4 m and + 1–2 m above the present thalweg. Available radiocarbon data and archeological remains collected in fan sediments and inset terraces enable the construction of a preliminary hypothesis about the progressive incision of the fan body from pre-historical to historical times. Proximal fan aggradation took place during the Early Holocene before ~ 7900–7700 cal. yr. BP and continued until the Late Neolithic to Calcolithic Period (~ 5500–4200 cal. yr. BP) when the fan surface stabilised, and channel incision generated a first fanhead trench. Subsequent infilling of the fan trench led to the development of the upper terrace level (+ 8–9 m) which merged with the palustrine environments 23 km downstream of Lorca, feeding distal fan lobes during Late Bronze Age and Post-Roman times. The second terrace level (+ 5–6 m) is a cut & fill episode of about 5 m thickness developed from Roman times, and dated to ~ 1700 to 950 cal. yr. BP. The geometry and altimetry of the upper terrace level, together with the occurrence of different steps in the longitudinal profile of the river at mid to distal fan locations, strongly suggest that the incision of the ancient fan channel was assisted by intersection point headcut development (sensu [Harvey, A.M., 1978. Dissected alluvial fans in southeast Spain. Catena 5, 177–211.]) at proximal-mid fan locations, but by headward erosion exerted by neighbouring drainage basins at distal palustrine environments. Therefore, the Lorca fan exemplifies the behaviour of large-sized fans in its transition from pure alluvial environments to fluvial ones, and its eventual incipient integration into a regional drainage network subject to a dynamic base-level during the historic period., This work has been supported by the Spanish DGES Projects CGL2005-04655/BTE and CGL2005-01336/BTE. The authors are grateful to the constructive comments of Martin Stokes (Plymouth, UK), Francisco Gutiérrez (Zaragoza, Spain), Andy Plater and Adrian Harvey (Liverpool, UK).

Tectonic activity of SE Spain is evaluated through the application of a general morphometric analysis over 17 different mountain fronts. The selected fronts are distributed along the two most prominent crustal-scale structures of the Mediterranean sector of Spain: The Eastern Betic Shear Zone (EBSZ) and the Valencia Trough. Geomorphic indexes used in this study are Mountain-front sinuosity index (Smf) and Valley floor/width ratio (Vf). This work is largely based on the Smf/Vf regression analysis of the studied fronts together with previous available data from SW USA. The development of mountain fronts in both different lithologies and tectonic contexts enabled characteristic morphometric signatures for different activity scenarios (tectonic activity classes) to be obtained. This study thus indicates that variations of mountain front geomorphology triggered by different styles of faulting can be detected by morphometric analysis. It is demonstrated that discrete uplift rates of 0.15-0.08 m/ka are sufficient to keep relatively low Smf values down to 1.4 in Active fronts (Class 1). Taking into account the reported uplift rates and preliminary palaeoseismic data for some of the Class 1 studied fronts, recurrence periods for surface rupture events can be theoretically bracketed for SE Spain. Recurrence periods for Class 1 fronts could theoretically range between 10,000 and 12,500 years for maximum slip conditions, and 1750 and 2600 years for minimum slip conditions. Inactive fronts (Class 3) develop under uplift rates down to 0.03 m/ka, and tested recurrence intervals for rupture events range between 25,000 and 50,000 years. Class 2 fronts of intermediate characteristics and activity display uplift rates between 0.07 and 0.03 m/ka., This work has been supported by the Spanish DGES Projects PB98-265 (USAL) and PB98-514 (CSIC). The authors wish to thank M. Stokes, R. Basili and A. Mather for useful comments on earlier versions of the manuscript.

[EN] The evolution of Neogene and Quaternary littoral basins in the Eastern Betic Cordillera is largely related to tectonic activity along the Eastern Betic sinistral shear zone.Detailed mapping of sedimentary units in these basins, together with sedimentologicaland paleomagnetic analysis lead tothe proposal of a new chronostratigraphie frameworkfor Pliocene and Quaternary deposits.This chronostratigraphie setting rejects the synchronous character of the “Pliocene Unite” previously referred toas:“P.I” (grey-blue marls), “P.H” (yellow calcarenites), and “Р.Ш” (variegated silts and clays). Instead, tectonics would have controlled the paleogeographic evolutionof the Eastern Betic realms, causingthe lithofacies to occur repeated in space and time. The Plio-Pleistocene boundary in these basins is not accompanied by changes in geodynamic behaviour or climatic conditions. According to the paleomagnetic data, these changes occurred at different times during the Pleistocene in the different studied basins., [FR] L’évolution des bassins littoraux néogènes et quaternaires dans les Cordillères Bétiques orientales est étroitement liée à l’activité tectonique le long du couloir décrochant sénestre, bétique oriental. La cartographie détaillée du remplissage sédimentale des bassins et les analyses sédimentologiques et paléomagnétiques ont permis d’établir une nouvelle échelle chronostratigraphique pour les dépôts pliocénes et quaternaires. Elle remplace les interprétations antérieures fondées spécialement sur les corrélations stratigraphiques, et abandonne le traitement des unités pliocénes traditionnelles (P.I marnes gris-bleues; P.II grès calcaires jaunes; Pill limons et argiles bigarrés) en tant qu’unités isochrones. L’évolution paléogéographique de la région, contrôlée particulièrement par la tectonique, a entraîné le déplacement et la répétition des faciès dans l’espace et dans le temps. La limite Plio-PIéistocène dans les bassins n’est pas acompa-gnée par des changements du comportement géodynamique ni des conditions climatiques. D’après les données paléomagnétiques, ces changements ont eu lieu dans les divers bassins à différents moments du Pleistocène.

Deposits of the Last Interglacial on the south and southeastern coasts of Spain are shallow marine and coastal sediments, with a warm fauna of Strombus bubonius. These units exhibit a diversity of morpho-sedimentary models controlled by the tectonic activity of the Mediterranean area, which is closely related to the approximation of Africa and Iberia during the Quaternary. There are three well-dated peaks of maximum sea level (T-I: isotopic substage 7a, T-II: isotopic substage Se, T-III: isotopic substage 5c). A younger episode, T-IV, probably corresponds to the isotopic substage 5a. Episodes T-II, T-III and T-IV were laid down during Last Interglacial age. In addition, three Holocene peaks of maximum sea level: H1 ca. 5100 yr B.P., H2 ca. 3500 yr B.P. and H3 ca. 2400 yr B.P. were found. The three main peaks of the Last Interglacial correspond to the morpho-sedimentary Tyrrhenian units T-II, T-III and T-IV, deposited during a time span of sorne 45,000 years. Several smaller oscillations can be distinguished within each of these units as subunits separated by erosional surfaces. At least three of such mapable subunits were distinguished within the peak T-II (Se); each lasted ca. 10,500 yr. As the positive oscillations of sea level (H1, H2, and H3) recorded during the present Interglacial (Holocene) are much shorter, we infer that they are smaller-scale fluctuations (2500-1100 yr cycles) within the first oscillation (duration: ca. 10,500 yr) of the first Holocene peak of sea level which has not yet been completed. In addition to changes of sea level, the vertical and lateral arrangement of morpho-sedimentary units, which can be designated as the stratigraphic architecture, depends on tectonics and oceanography, including geoidal and steric changes and coastal dynamics. The coastal dynamics factor largely depends on the exchange of waters between the Atlantic and the Mediterranean. Maximum incursions of water coincides with warm periods (highstands) when the coastal accretion increases. The tectonic factor greatly influences and modifies the effects of sea-level changes in the coastal areas of tectonically-active regions such as the Mediterranean. Areas with tectonic uplift will be characterized by a staircase of prograding gravelly beaches, whereas sinking areas will favour the deposition of vertically stacked sequences with coastal onlap of barrier island and lagoon deposits. Rates of sea-level rise for the coming years of 1 cm/yr, have been suggested by sorne authors. These gradients greatly exceed those produced by any tectonic factor in the Spanish coast during the last 100 kyr. Shoreface erosion and transgression with landward migration of barrier islands and lagoons will occur in subsiding areas (Murcia-Alicante and Valencia), even with relatively low rates of sea-Ievel rise Oess than 0.5 cm/yr). Higher rates of sea-level rise (0.5-1 cm/yr) will increase the transgressive trend. Areas with subsidence rates higher than 7.5 cm/kyr (Mar Menor and Oval of Valencia) are prone to transgression and erosion of barrier islands and lagoons both in the cases of stable and rising sea levels. Risks are smaller in areas with lower rates of subsidence (La Mata, Santa Pola and Torrevieja lagoons) when a stable sea level is considered; however, any rise of sea level will trigger coastal erosion.

Five main faulted mountain fronts can be recognized on the margins of the Guadalentin Depression. The alluvial fans associated with each show different geomorphologic assemblages and morphometric characteristics. All fan groups show a broad similarity in their sedimentary sequences: earlier phases dominated by aggradation and later phases mainly dissectional but with distal agradation, that seems to be controlled by the regional climatic and tectonic trends over the Quaternary period. However, the different alluvial fan assemblages associated with each fan group are controlled by the different tectonic patterns related to each mountain front. From the study of the relationships between alluvial fans and drainage basin morphometric variables four types of fan can be distinguished. Each type shows a distinct pattern in the relationships of the two sets of residuals derived from fan gradient/drainage basin area and fan area/drainage basin area regression equations, reflecting relationships between sedimentation and alluvial fan morphometric properties.

The analysis and study of geomorphological features such as: sequence and geometrical disposition of Quaternary geomorphological units; hanging valleys; captures, straight scarps; triangular facets; tilted and deformed deposits..., together with the application of geomorphic indices such as: Stream gradient index; mountain front sinuosity index and ratio of valley-floor width to valley height, all of them indicators of recent tectonic activity, constitute the basis for the realization of a neotectonic cartography. Likewise an analysis of the longitudinal profiles of the several rivers crossing across the studied area and their sinuosity, has been made. From all that, it can be deduced that during the Quaternary the neotectonic activity in the centresouthern sector of the Madrid Basin has been important, mainly during the early-middle Pleistocene transit, when the capture of the River Manzanares by a tributary of the River Jarama, is produced by the southwestward-tilting of the La Maranosa block. Most of the geomorphological features indicators of neotectonics are associated to the large gypsum scarps bounding the main rivers, and are developed troughout the whole Quaternary, including the Holocene. On the other hand the study of the longitudinal profiles of the rivers shows a marked deviation from the theoretical equilibrium profile, being all of them affected by numerous inflections which in many cases correspond to the passing of faults perpendicularly to the river floor. Likewise the sinuosity degree of the rivers is conditioned at a small scale, by the passing of faults, or tectonic activity lines, parallel or perpendicular to the valley.